Preparation And Sodium Storage Properties Of High Capacity Antimony Based Nanocomposites

Nano materials have been widely studied in solar cells,lithium-ion batteries,sodium ion batteries,photocatalysis and other fields.The development of lithium-ion battery is hindered by the difficulty and scarcity of lithium mining.However,sodium in the earth's crust is abundant and easy to exploit.In addition,it is located in the same main group with lithium and has similar chemical properties.Therefore,many researchers regard sodium ion battery as a substitute for renewable resource storage applications,which will have a better competitive advantage in the future.Traditional graphite anode materials can not meet the needs of sodium ion intercalation and exfoliation due to the small layer spacing,so it is the focus of sodium ion battery research to find excellent anode materials.Antimony based nano materials(Sb₂S₃?Na Sb(OH)₆?Na Sb S₂?Sb₂S₅)are important representatives of nano semiconductor materials,which have high theoretical specific capacity.Therefore,it is of great value to study and apply them as anode materials for sodium ion batteries.In this paper,starting with the morphology and structure of the synthesized materials,the electrochemical properties of the prepared materials as anode materials for sodium ion batteries were studied,The main research contents are as follows:(1)The preparation and properties of Sb₂S₃ and Sb₂S₃/C nanorods:the one-dimensional diameter of 80-190 nm and the length of about 40 nm were prepared by solvent heat method,using antimony trichloride(Sb Cl₃)and sodium sulfide(Na₂S·9H₂O)as raw materials,polyvinylpyrrolidone(PVP)as surfactant,glycol as auxiliary solvent,and at 200?and reaction time of 12 h.The effects of surfactant content and reaction time on the morphology and properties of the products were discussed,and the formation mechanism of the products was studied.When Sb₂S₃/C nanorod composite is used as the negative material of sodium ion battery,it has excellent sodium storage performance.the first discharge specific capacity is 1019.2m Ah/g at the current density of 0.2 A/g,and the capacity remains at 566.8 m Ah/g after 50 cycles.When the current density is increased to 0.5 A/g,the capacity remains480.4 m A h/g after 100 cycles.(2)The reparation and properties of Na Sb(OH)₆/Na Sb S₂ nanoparticles:the nano particles were prepared by solvent heat method with antimony trichloride(Sb Cl₃),sodium sulfide nine(Na₂S·9H₂O)and urea as raw materials,ethanol as solvent,temperature of 140?and reaction time of 10 h.The effect of different urea content on its morphology,structure and electrochemical properties was discussed.The results show that the performance of Na Sb(OH)₆/Na Sb S₂ prepared by adding 2.0 g urea is the best.At the current density of 0.2 A/g,the first discharge specific capacity is 1135.2m Ah/g.after 100 cycles,the capacity remains at 437.1 m Ah/g.when the current density increases by 1 A/g,the capacity remains at 440.8 m Ah/g after 100 cycles.(3)The preparation and properties of Sb₂S₅ and Sb₂S₅/CNTS nanomaterials:Sb₂S₅ nanoparticles were prepared by using antimony pentoxy,vulcanization as solution,tartaric acid as raw materials,concentrated hydrochloric acid and water as solvent,and at oil bath temperature of 100?.In order to explore the optimum composition ratio of the composite,the effects of solvent and antimony pentoxy content on the morphology and properties of Sb₂S₅ nanoparticles were discussed,and the mechanism of sodium storage of Sb₂S₅ nanoparticles was studied.In order to improve the conductivity and stability of the materials,the carbon nanotubes were composite with Sb₂S₅.The effects of the different contents of carbon nanotubes on the morphology and electrochemical properties of the composite were studied.When the current density is 1 A/g,the discharge specific capacity of Sb₂S₅/CNTS composite can reach 1004.0 m Ah/g in the first cycle.After 100 cycles,the capacity remains at 387.8m Ah/g.when the current density is increased to 2 A/g,the capacity remains at 396.3m Ah/g after 100 cycles.